The present invention relates to a control system of a vehicle such as a car and an automobile using the same, particularly to a vehicle control system capable of reducing the cost of the control system and an automobile using the same.
FIG. 11 is a block diagram of a conventional vehicle control system of a car or the like.
The vehicle control system 601 is constituted of an electronic control unit (ECU) 1xe2x80x2, a plurality of sensors 2xe2x80x2, and a plurality of actuators 3axe2x80x2, in which a predetermined operation is performed by the electronic control unit 1xe2x80x2 set in a cabin in accordance with signals of the sensors 2xe2x80x2 provided in the engine room of the vehicle to drive the actuators 3axe2x80x2. 
The electronic control unit 1xe2x80x2 is constituted of an input interface (input I/F) 11xe2x80x2, an arithmetic processing section 10xe2x80x2, and an actuator driver 4xe2x80x2, in which the input I/F 11xe2x80x2 processes signals sent from the sensors 2xe2x80x2 and outputs them to the arithmetic processing section 10xe2x80x2, the arithmetic processing section 10xe2x80x2 performs predetermined operations and outputs an optimum signal to the actuator driver 4xe2x80x2, and the actuator driver 4xe2x80x2 drives the actuator 3axe2x80x2 serving as a load through a connector 3bxe2x80x2. The actuator driver 4xe2x80x2 is concentratedly set in the electronic control unit 1xe2x80x2.
In the above vehicle control system, an engine control system of a car is a system for optimally controlling an engine by performing predetermined operations by a microcomputer serving as an arithmetic processing section in an engine control unit serving as an electronic control unit in accordance with signals sent from an engine-speed sensor, a water-temperature sensor, and an intake-air-flow sensor, outputting a fuel injection signal to a driver for driving an injector and a switching signal and a valve-opening-degree adjustment signal to a driver for driving various valves and relay switches.
In the case of the vehicle control system 60xe2x80x2 in FIG. 11, the actuator driver 4xe2x80x2 is concentratedly set in the electronic control unit 1xe2x80x2. Moreover, there is a publicly-known example in which actuator drivers are dispersed not in an electronic control unit but by making the drivers respectively correspond to an actuator to be driven. The official gazette of Japanese Patent Laid-Open No. 79841/1996 discloses the art of a communication connector of a vehicle electronic controller for building each of the above dispersed actuator drivers in a connector connected to an actuator in order to improve the versatility of the actuator. Moreover, as other conventional examples of vehicle control systems, various arts are disclosed in the official gazette of Japanese Patent Laid-Open No. 275801/1999 and the like.
In the case of a vehicle control system, a comparatively large current (approx. several amperes) generally flows through an actuator driver when driving an actuator. The actuator driver frequently uses a power transistor or power MOS in which Joule heat is produced due to an on-resistance because the comparatively large current flows when power is turned on.
Therefore, as shown by the conventional vehicle control system 60xe2x80x2 in FIG. 11, when the actuator driver 4xe2x80x2 is concentratedly set to one place in the electronic control unit 1xe2x80x2, a problem occurs that the calorific value of the whole of the electronic control unit 1xe2x80x2 is increased by the actuator driver 4xe2x80x2 serving as a heat-producing part and the increase of the calorific value may affect control.
Particularly, in the case of a recent car, the above electronic control unit tends to be set not in a cabin but in a vehicle engine room in order to reduce the harness cost and assembling man-hours and thereby the electronic control unit is exposed to a severer temperature environment. Therefore, to avoid the electronic control unit from being exposed to the environment, it is necessary to use a radiation component such as a heat sink or radiation fin in order to radiate heat. Thus, a problem occurs that the manufacturing cost and the cost of the whole vehicle control system in its turn increase.
In this case, as the control system disclosed in the Japanese Patent Laid-Open No. 8-79841 (1996), it is considered to make actuator drivers respectively serving as a radiation component correspond to an actuator to be driven and disperse the drivers to the actuator side. However, it is not sufficient to merely disperse the actuator drivers because the following are indispensable for a present engine control system: a self-diagnosis function for diagnosing a trouble such as a disconnection or short circuit of an actuator and communicating the diagnosed state to an arithmetic processing section of an electronic control unit, a self-protection function for preventing an actuator driver from being broken down due to overcurrent or overheat when the above trouble occurs, and a timer circuit when PWM (Pulse Width Modulation)-controlling the dispersed actuator in a multiplex communication system through a serial communication line.
That is, the present inventor obtained the new knowledge that in the case of a vehicle control system having an electronic control unit and a plurality of actuators, it is necessary to disperse actuator drivers to the actuator side in order to reduce the cost of the vehicle control system, provide a self-diagnosis section, a self-protection section, and a communication-control section for each of the actuator drivers and make the drivers independent in order to keep the reliability and functionality of the system even after the actuator drivers are dispersed. In the case of the above prior art, however, the actuator drivers are not dispersed to each actuator side separately from the electronic control unit or the actuator drivers are not dispersed to easily radiate heat even if the drivers are set to the outside of the electronic control unit. Moreover, the drivers are not independent drivers capable of constructing an actual system. Therefore, it is not particularly considered to maintain the reliability and functionality of the control system even if reducing the radiation-component cost of the vehicle control system by reducing the heat produced in the electronic control unit and dispersing the actuator drivers.
The present invention is made to solve the above problems and its object is to provide a vehicle control system for reducing the cost of the control system by dispersing actuator drivers and controlling the heat produced in an electronic control unit, making the actuator drivers independent and keeping the reliability and functionality of the control system even after dispersing the actuator drivers and provide a car using the system.
To achieve the above object, a vehicle control system of the present invention is a vehicle control system basically comprising an electronic control unit and a plurality of actuators. The control system has actuator drivers for driving the actuators at the actuator side and the actuator drivers are made independent by respectively having a self-diagnosis section, a self-protection section, and a communication control section and dispersed correspondingly to the actuators one-to-one.
In the case of the vehicle control system of the present invention constituted as described above, the actuator drivers are set to the actuator side separately from the electronic control unit and dispersed correspondingly to the actuators one-to-one. Therefore, it is possible to reduce the cost of the control system by controlling the heat produced in the electronic control unit. Moreover, because each of the actuator drivers is made independent as a system, it is possible to keep the reliability and functionality of the control system even after dispersing the actuator drivers.
Moreover, in the case of a specific mode of a vehicle control system of the present invention, the actuator drivers respectively have a timer section.
Furthermore, in the case of another specific mode of the vehicle control system of the present invention, the actuator drivers are built in connectors or adapters connected to the actuators, removably mounted on outsides of the connectors or adapters connected to the actuators and electrically connected with the connectors or adapters, or built in the actuators.
Furthermore, in the case of still another mode of the vehicle control system of the present invention, the communication control section of each of the actuator drivers has a serial communication control section or a radio communication control section.
Furthermore, the actuator drivers are fabricated on a semiconductor substrate and respectively used as an IC or directly mounted on a metallic member not through the substrate and formed integrally with connectors or adapters connected to the actuators or integrally with the actuators through mold mounting.
Furthermore, the electronic control unit is set in the engine room of a vehicle or in a car using the vehicle control system.